The present invention relates to audio mixers, and more particularly to the shaping of automatic audio crossfades to provide a more pleasingly aesthetic sound as a transition is made from one audio mix to another.
In audio production one commonly performed operation is a crossfade where a controlled smooth transition is made between one audio mix and another. On a manually controlled system an operator fades up a source being brought into the mix while fading out another source being removed. Due to the nature of sound the sources must be mixed in such a manner that both sources are down 6 dB from their full on settings midway through the mix. Mixing systems have been developed to automate this process, using addition rules for sound sources in the mixing algorithm. An automatic crossfade using the theoretical algorithm results in a transition that some listeners find too abrupt because at either end of the transition the level of the lower gain source is changing rapidly and is perceived as a cut rather than a fade. Human operators instinctively correct for this abruptness at the ends of the crossfade by modifying their manual motion. The perceived cut effect is exaggerated if the automatic control system runs on a sampling rather than continuous basis where large gain changes cannot be produced smoothly.
Therefore what is desired is an automatic audio crossfade process that modifies the theoretical crossfade algorithm to produce a smooth transition that is pleasing to a listener.